A Buffer Copy without Checking Size of Input vulnerability in the Session Initialization Protocol (SIP) ALG of Juniper Networks Junos OS on MX Series and SRX Series allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS). When memory utilization is high, and specific SIP packets are received, flowd/mspmand crashes. While the system recovers automatically, the disruption can significantly impact service stability.

Continuous receipt of these specific SIP packets, while high utilization is present, will cause a sustained DoS condition. The utilization is outside the attackers control, so they would not be able to deterministically exploit this. This issue affects Junos OS on SRX Series and MX Series: All versions before 22.4R3-S7, from 23.2 before 23.2R2-S4, from 23.4 before 23.4R2-S5, from 24.2 before 24.2R2.